Pilot fuel flow control



Jaim EL X95@ m, W, JQHNSQN ZQ PILOT FUEL FLOW CONTROL Filed July $3,1944.

INVENTOR. E05/ W Joy/VSGA! Patented Jan. 31, 1950 y y y 2,496,214

UNITED STATES PATENT yOFFICE:

Roy W. Johnson, Milwaukeatwis.

Application J uly 8, 194.4, feral No. 544,0;55

This invention relates to improvements in devicesior controlling theflow of fuel oil from a reservoir to a burner of the gravity feed typeand particularly to means controlling the supply of oil to the pilotflame of such burner.

Devices of the character to which the present invention relates areknown to the art as shown for example in Patent 2,120,364, issued to RoyW. Johnson on J-une 14, 1938. In such devices an inlet valve `actuatedby a oat controls the iiow of oil to maintain a substantially constantlevel of oil `in a chamber. Oil ows from the chamber to one or moreburners under the control of a metering valve or valves adjustablemanually and/ or thermostatically. y

A pilot flamemust be kept constantly burning to provide for ignition ofthe oil supplied to the main burner so that oil must be constantlysuppliedto the` pilot flame regardless of the 'position` of the valvefor metering the flow `of oil to the main burner. The volume of oilnowing to the burner is varied by temperature changes or changes in thecomposition of the oil itself and means must therefore be Iprovided :foradjusting the flow of fuel to the :pilot to compensate for such changes.A passage o f relatively smallcross sectional area can be used tocontrolthe ow of provide means which may be readily adjusted totcompensate for changes in the flow Aof oil to the pilot name or burnerof an oil burner.

. Another object of!l the presentinvention isito provide a device for=cor'itrolling vthe flow of [fuel o il to a pilot flameorlpilot burnertosecure the I desired volume of oil regardless of changesV in thecharacteristics of the oil. gw.

Another object of the invention is to tcontrol sectional area, orsci-called capillary passage, of which the effective length maybereadily adjusted and which may easily b e `kept free from materialsdepositingifrom the oil.

Another objectof the invention is to provide a capillary passage forcontrolling the now of oil to a burner for pilot operation in which apart of` the means forming the Ipassage may removed ,i

for cleaning without disturbing adjustment-oi the device for either itscontrol of flow for main flame `or 'pilot flame W operation I- of the.burner.` .l .I i Objects and-advantages other than those aboven set `fort1iwill pibe.. apparent *from` xthe` following.

I 9 Claims. (Cl. 137;-21) i i i the flow of oil during pilot .operationof a burner.

by means of a passage of relatively small cross-` 2 description whenread in connection with the accompanying drawings, in which:

Fig. 1 is a top plan view of a constant level oil control deviceembodying the present invention with all of the parts not essential todisclosure of the present invention omitted therefrom;

Fig. 2 is a vertical cross-sectional View taken on the plane of thebroken line II-II of Fig. 1;

Fig. 3 is a vertical sectional view taken on the plane of the lineIII-III of Fig. 2;

Fig. 4 is an enlarged fragmentary View of 'the structure forming acapillary ypassage between the casing chamber land a portion of theoutlet passage therefrom, in a constant level oil flow control device;and

Fig. 5 is a vertical sectional View similar to that i shown in Fig. 3but illustrating a modified embodiment or" the present invention.

Referring more particularly to the drawings by characters of reference,numeral II designates a casing -divided substantially into a mainchamber I2 and an auxiliary chamber I3 by a partition or ydarn I4 havingits crest slightly above the normal level of the oil to be maintained in'the main chamber. The casing is formed with ears I5 for attachmentthereto of a cover I6 by suit--` .able means such as screws I 1. A fuelsupply conduit 20 is preferably formed integral `with the casing I I andis provided with a nipple 2| by which a pipe connection with a reservoirfor fuel (not shown) may be made. The conduit 20 is adapted to receive asuitable filter such as is shown for example in the above patent.

An opening is formed in a thickened portion 23 in the wall between themain chamber I2 and the conduit 2D and is internally threaded to receivea valve casing or body 24 which is formed with an axial Ipassage andtransverse passages providing for communication between the conduit Iand the chamber I2 under the control of a valve 25. The valve 25 ispreferably formed as a needle having va beveled end seating on ashoulder 26 formed inthe valve body 24 and preferably adjacent thevjuncture of the axial and transverse passages therein. The valve 25controls the ow of fuel oil from the cond-uit 20 in such manner as notch29 inthe dam I4 into the auxiliary cha-mf ber I3 to-release a latchmechanism disclosed in` the above identied patent, `which positivelycloses the inlet valve 2 5.- I

The casing II is provided with a passage 3| terminating in nipples 32and"Sato-whichpipes vmay be connectedforfseverally supplying fuelgoiltoaiburnerorburners (not shownl-l--I It-willbeunderstood that when onlyone burner is to be supplied, the nipple not used is closed by asuitable plug. A valve casing or body 3d is inserted in one end ofpassage 3| and is formed with both axial and transverse 'passagesthrough which oil may flow `under the control of a valve 35. The valveseats on a shoulder 36 formed in the valve body 34 and is formed with atubular portion 3l extending beyond the seat and Iprovided with slots 38for the purpose lof allowing precise metering of the quantity of oilsuppiied to the main burner. The valve 35 has mounted thereon a collar39 havin-g a ringer 40 extending therefrom and engaged between guideribs 6I on a `wall of casing I I.

- Fuel is supplied for pilot operation of the main burner 'from the mainchamber. l2 .by Way of a conduit lay-passing the metering. valve 35 andiiows through such lay-pass independently of the action of the meteringvalve 35. As Shown in Fig. 3, a well is formed in one side of the casingI and is connected at its lower end with the outlet passage 3l beyondthe outlet valve seat 35 by tubing 4l. It will be seen from the drawingsthat the well i5 is within the main chamber i2 of the device and thatoil may accordingly flow through such well and the tubing 47 to theoutlet passage 3| except as such flow is controlled by a plug having aportion 5G and a portion 5|'. The plug portion 5D seats in the well 46and blocks off ilow of oil therethrough except for such oil as may ovvthrough a groove on the plug portion 5% and extending from the upperedge of the well to the lower end of the plug portion. The groove in theplug portion 50 is shown as being formed by a'relatively coarse thread52 which fits closely into thel well d6 so that the outside diameter ofthe thread in cooperation with the Wall of the Well deiines a passage ofrelatively small crosssectional area or a capillary passage which allowsflow of oil from the chamber I2 through the well G6 at a rate dependenton the effective length of the passage, that is the length of the threadwhich is within the well itself.

The plug portion 5| is of less diameter than the plug portion 5i) and isthreaded to engage with an adjusting nut seating on the wall forming thewell 45 and forming a seat for one end of a compression spring 56 havingits other end seated on the shoulder formed by the juncture of the plugportions 5b and 5|. Rotation of the 'nut -55 is limited byl a pin 5lextending from the nut and engaging with al rib 53 on the casing sidewall. Theposition of the plug 59-5i in the Well 46 is adjusted byrotation of the plugin the nut byineans o'i` a suitable tool engagingthe slotted upperend of the plug through liole in the Acover I6, whichis normally closed by a but-V ton 6l). Rotation of the plug is limitedby a collar 62 which is threaded on the plug portion or stem 5| andcontacts on the nut 55 when the plug is in position to secure themaximum eliective length of the capillary passage. The collar 62 has anear engaging a stop 63 to limitrotation of the collar. The entire plugis held in adjusted position by a springtil seatedbetween a shoulder onthe plug stem 5| and the cover it. The plug 55-56 is formed with anaxial passage therethrough to vent any gas released from the oil in thecapillary by-pass and thus prevents so-called binding of the by-pass.

In the use of the device, oil flows from the chamber I2 beneath aportion of the nut 55 and enters the capillary passage defined by thethread 52 and the wall of the Well 45. Oil ows downwardly through thecapillary passage, as indicated by the arrows, into the Well e6 andthence through the tube II'I to the outlet passage 3|. The amount of oilowing through the above path is determined by fluid friction on theWalls and hence by the length of the capillary passage which is readilyadjusted merely by turning the plug to increase or decrease the lengthof the groove formed by the thread Within the Well. If the capillarypassage becomes partially or wholly clogged, removal of the cover I6 andthe spring 64 allows the plug Sil- 5l to be lifted out of the Well '46for cleaning. It Will be seen that the entire area and length of thecapillary passage is then exposed and can be thoroughly cleaned. Ifcareis taken that the nut is/not turned dur-Y ing the cleaning operation,replacement 0i the cleaned plug in the Well with the pin 5l' between therib 58 avoidsany necessity for readjustments not required by temperatureor oil composition changes.

The structure shown in Fig. 5 is generally similar to and functions in amanner generally similar to that shown in Fig. 3 excepting that the oilflows upwardly through the capillary passage. In the modified structure,a Well 66 is formed with aninlet @l and an outlet 68. A solid plug withportions Se and l@ is provided on its portion 69 with a coarse thread 7|tting into the well and, in combination with the Well, denes a capillarypassage of'which the effective length may oe determined by positioningthe plug portion e9 relative to the outlet 68. An adjusting nut l2 isthreaded on the plug stem portion 'I0 and engages a locking bar 'I3which is preferably guided in its movements by ribs 'M on the casingWall. A lock Washer 'I5 contacts both the nut 'l2 and the locking bar'I3 and prevents accidental movement of the plug under the influence ofa spring i6 between the nut and the cover. The oil flowing through thecapillary passage is discharged into a sump 'il' formed in the casingadjacent the well 66 and from there flows through Y the sump outlet 'I8into the casing outlet passage 3|.

It will be seen that the present invention provides a structure in whicha capillary passage bypasses the main flame ow control valve for aliquid fuel burner, thus providing for continuous flow of fuel to theburner during the pilot portion of its cycle. ends ci the capillarypassage are both below the level of the fuel maintained in a supplychamber so that the volume of fuel flowing through the passage isvariable merely by varying the eiiective length of the passage. Suchvariation is obtained merely by adjusting they position of a groovedplug in a well, both the plug and the Wall of the well being required todefine the capillary pas- The position of the plug is readily adjust-gentire area and length of the groove for maintenance of the initialcross-sectional area andthe original frictional characteristics of thegroove Wall. And the plug is readily replaced without disturbing theadjustment of the metering valve or change in the setting of the'by-pass.

Although but two embodiments of the present invention have beenillustrated and described, it will be apparent to those skilled in theart that various changes and modincations may'bemade therein without'departing from the spirit of the The inlet and the discharge inventionor from the scope of the appended claims.

I claim:

1. In a device controlling the iiow of liquid fuel to a burner of thegravity feed type, a casing having a fuel supply chamber provided withan outlet passage and a well connected with the chamber and the passage,and a plug mounted in the well for axial movement therein and denningwith a portion of the wall of the well a capillary passage therewith formaintaining a continuous and limited ow of fuel to the burner, and meansfor axially adjusting the plug within the well to vary the effectivelength of the capillary passage.

2. In a device controlling the flow of liquid fuel to a burner of thegravity feed type, a casing having a chamber with an outlet passagetherefrom and a well connected between the chamber and the passage, anda plug mounted in the well and having a groove coacting with the wall ofthe well to dene a capillary passage for maintaining a continuous flowof fuel to the burner and means for adjusting the plug axially of thewell to bring portions of the groove into and out of the path of liquidnow through the well.

3. In a device controlling the ow of liquid fuel to a burner of thegravity feed type, a casing forming a fuel supply chamber with an outletpassage therefrom and a well connected between the chamber and thepassage and by-passing a portion of the passage, a plug mounted in thewell and having a helical groove coacting with the wall of the well todefine a capillary passage for maintaining a continuous flow of fuel tothe burner. and means for axially adjusting the position of the plug inthe well to vary the length of the capillary passage in the path ofliquid iiow through the well.

4. In a device controlling the flow of liquid fuel to a burner of thegravity feed type, a casing defining a chamber and an outlet passagetherefrom and a Well connected with the chamber and the passage, a plughaving a groove coacting with the wall of the Well to define a capillarypassage for maintaining a continuous ilow therethrough of fuel from thechamber to the passage and to the burner, a spring biasing the plug intothe well, and means for limiting the action of the spring and adjustableto vary the position of the plug in the well.

5. In a device controlling the ilow of liquid fuel to a burner of agravity feed type, a casing deiining a chamber and an outlet passagetherefrom and a well connected with the chamber and the passage, a plughaving a groove coacting with the wall of the well to define a capillarypassage for maintaining a continuous iiow of fuel therethrough from thechamber to the passage and to the burner, the plug being movable axiallywithin the well to vary the capillary effective length of the passage,means urging the plug into the well, and means limiting movement of theplug by the first said means.

6. In a device controlling the flow of liquid fuel to a burner of agravity feed type, a casing delining a chamber and an outlet passagetherefrom and a well connected with the chamber and the passage, a plugmounted within the well and having a helical groove extending from endto end of the plug and coacting with the wall of the well to define acapillary passage for maintaining a continuous flow of fuel therethroughfrom the chamber to the outlet passage and to the burner, a

spring acting along the longitudinal axis of the plug and urging theplug into the well, and means limiting movement of the plug by thespring and adjustable to vary the length of the groove in the path ofliquid flow through the well.

7. In a device controlling the flow of liquid fuel to a burner of thegravity feed type, a casing having a well between a supply chamber andan out let passage, the wall defining the well having vertically spacedinlet and outlet apertures therein connecting the well with the chamberand the outlet passage respectively, a plug in the well for defining acapillary passage therewith between said inlet and outlet apertures tomaintain a continuous ow of fuel to the burner, and means for axiallyadjusting the position of the plug in the Well to bring an intermediatepart of the passage defining a portion of the plug into alignment with acontrolling one of said apertures to thereby vary the effective lengthof the capillary passage below said controlling well wall aperture andin the path of liquid flow through the well.

8. In a device controlling the flow of liquid fuel to a burner of thegravity feed type, a casing having a well between a supply chamber andan outlet passage, the well wall having vertically spaced inlet andoutlet apertures therein connecting the well with the chamber and theoutlet passage respectively, a plug having a groove coacting with a wallof the well for defining a capillary passage between said inlet andoutlet apertures to maintain a continuous flow of fuel to the burner,and means for axially adjusting the position of the plug in the well tobring an intermediate part of the groove into alignment with acontrolling one of said apertures to thereby vary the effective lengthof the capillary passage below said controlling well wall aperture andin the path of liquid ow through the well.

9. In a device controlling the flow of liquid fuel to a burner of thegravity feed type, a casing defining a chamber and an outlet passagetherefrom and a well bypassing a portion of the outlet passage, the wellwall having vertically spaced inlet and outlet apertures connecting thewell with the chamber and the outlet passage respectively, a plug in thewell and having a groove coacting with a Wall of the Well to define acapillary passage between said inlet and outlet apertures formaintaining a continuous flow of fuel to the burner, the plug beingadjustable axially in the well to bring portions of the groove above acontrolling one of said apertures in the well wall to thereby vary theeffective length of said capillary passage between said inlet and outletapertures, the plug having a passage vertically therethrough for ventinggases from the liquid owing through the well, a spring urging the plugtoward the bottom of the well, and means limiting movement of the plugand adjustable to vary the plug position in the well.

ROY W. JOHNSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,858,557 Platt May 17, 19322,012,004 Hall Aug. 20, 1935 2,355,870 Johnson Aug. 15, 1944

